docs: def Tran(m, x, rhol, rhog, mul, mug, sigma, D, roughness=0, L=1):
      r'''Calculates two-phase pressure drop with the Tran (2000) correlation,
      also shown in [2]_ and [3]_.
  
      .. math::
          \Delta P = dP_{lo} \phi_{lo}^2
  
      .. math::
          \phi_{lo}^2 = 1 + (4.3\Gamma^2-1)[\text{Co} \cdot x^{0.875}
          (1-x)^{0.875}+x^{1.75}]
  
      .. math::
          \Gamma ^2 = \frac{\left(\frac{\Delta P}{L}\right)_{go}}{\left(\frac
          {\Delta P}{L}\right)_{lo}}
  
      Parameters
      ----------
      m : float
          Mass flow rate of fluid, [kg/s]
      x : float
          Quality of fluid, [-]
      rhol : float
          Liquid density, [kg/m^3]
      rhog : float
          Gas density, [kg/m^3]
      mul : float
          Viscosity of liquid, [Pa*s]
      mug : float
          Viscosity of gas, [Pa*s]
      sigma : float
          Surface tension, [N/m]
      D : float
          Diameter of pipe, [m]
      roughness : float, optional
          Roughness of pipe for use in calculating friction factor, [m]
      L : float, optional
          Length of pipe, [m]
  
      Returns
      -------
      dP : float
          Pressure drop of the two-phase flow, [Pa]
  
      Notes
      -----
      Developed for boiling refrigerants in channels with hydraulic diameters of
      2.4 mm to 2.92 mm.
  
      Examples
      --------
      >>> Tran(m=0.6, x=0.1, rhol=915., rhog=2.67, mul=180E-6, mug=14E-6,
      ... sigma=0.0487, D=0.05, roughness=0, L=1)
      423.2563312951232
  
      References
      ----------
      .. [1] Tran, T. N, M. -C Chyu, M. W Wambsganss, and D. M France. "Two-Phase
         Pressure Drop of Refrigerants during Flow Boiling in Small Channels: An
         Experimental Investigation and Correlation Development." International
         Journal of Multiphase Flow 26, no. 11 (November 1, 2000): 1739-54.
         doi:10.1016/S0301-9322(99)00119-6.
      .. [2] Kim, Sung-Min, and Issam Mudawar. "Universal Approach to Predicting
         Two-Phase Frictional Pressure Drop for Adiabatic and Condensing Mini/
         Micro-Channel Flows." International Journal of Heat and Mass Transfer
         55, no. 11–12 (May 2012): 3246-61.
         doi:10.1016/j.ijheatmasstransfer.2012.02.047.
      .. [3] Choi, Kwang-Il, A. S. Pamitran, Chun-Young Oh, and Jong-Taek Oh.
         "Two-Phase Pressure Drop of R-410A in Horizontal Smooth Minichannels."
         International Journal of Refrigeration 31, no. 1 (January 2008): 119-29.
         doi:10.1016/j.ijrefrig.2007.06.006.
      '''
      # Liquid-only properties, for calculation of dP_lo
      v_lo = m/rhol/(pi/4*D**2)
      Re_lo = Reynolds(V=v_lo, rho=rhol, mu=mul, D=D)
      fd_lo = friction_factor(Re=Re_lo, eD=roughness/D)
      dP_lo = fd_lo*L/D*(0.5*rhol*v_lo**2)
  
      # Gas-only properties, for calculation of dP_go
      v_go = m/rhog/(pi/4*D**2)
      Re_go = Reynolds(V=v_go, rho=rhog, mu=mug, D=D)
      fd_go = friction_factor(Re=Re_go, eD=roughness/D)
      dP_go = fd_go*L/D*(0.5*rhog*v_go**2)
  
      Gamma2 = dP_go/dP_lo
      Co = Confinement(D=D, rhol=rhol, rhog=rhog, sigma=sigma)
      phi_lo2 = 1 + (4.3*Gamma2 -1)*(Co*x**0.875*(1-x)**0.875 + x**1.75)
      return dP_lo*phi_lo2